An OPCW fact-finding mission for Syria "determined that chlorine was released from cylinders by mechanical impact in the Al Talil neighbourhood of Saraqib", the organisation said in a statement.

State Department Spokesperson Heather Nauert reported about the attack with the use of chlorine gas near the city of Saraqib on February 6.

The group said it came to its conclusion based on the presence of two cylinders at the site, which were determined to previously contain chlorine, along with witness testimony and environmental samples that demonstrated the unusual presence of chlorine.

Syria's Ambassador to the United Nations in Geneva Hussam Edin Aala rejected the accusation, saying, "Syria can not possibly be using chemical weapons because it very simply has none in its possession". Western observers said the use of helicopters in the attack suggested Syrian government involvement since the opposition did not have access to helicopters.

The OPCW's fact-finding mission was set up in 2014 to investigate repeated allegations of chemical weapons use in the Syrian conflict.

OPCW are now investigating another suspected chlorine attack that hit the town of Douma, Eastern Ghouta, in April that killed at least 60 civilians.

Medics have claimed the Douma attack on 7 April led to 40 deaths.

The team exhumed bodies as well as gathering over 100 environmental samples which are being analyzed in different OPCW-designated labs.

The FFM's report on the Saraqib incident has been shared with States Parties to the Chemical Weapons Convention.

The Douma chemical attack in April prompted missile strikes by the United States, France and Britain against chemical weapons facilities in Syria.

The UN secretary general, António Guterres, has been working privately to bridge the differences between Russian Federation and the west on how to reform the OPCW so that it has powers to attribute responsibility.